How David Lowered His A1c from 7.1% to 5.9% and Lost 20 Pounds

Article written and reviewed by Robby Barbaro, MPH
Published September 15, 2026

Meet David. After living with type 2 diabetes for about 15 years, he received a warning that made him reconsider how he was managing his health.

During a visit with his ophthalmologist for existing eye problems, David was told that he needed to get his diabetes under better control.

His doctor prescribed diabetes medications, including Jardiance, but David found that he couldn't tolerate it. By the end of 2025, his numbers were continuing to move in the wrong direction, and he began looking for another approach.

That's when he discovered Mastering Diabetes.

The idea immediately appealed to him: rather than relying exclusively on medication, could changing his diet and improving insulin sensitivity help him better manage type 2 diabetes?

David decided to find out.

Since beginning Mastering Diabetes, his A1c has fallen from 7.1% to 5.9%, his weight has dropped from 195 to approximately 175 pounds, and his energy has improved without compromising the active lifestyle he already enjoyed.

Just as importantly, David says the program taught him more about his own health and helped him understand that meaningful change requires consistency.

Looking for Another Way to Manage Type 2 Diabetes

David had been dealing with type 2 diabetes for approximately 15 years when his ophthalmologist encouraged him to take his blood sugar management more seriously.

His doctor prescribed medications, including Jardiance, but David couldn't tolerate Jardiance. By the end of 2025, he was increasingly concerned because his numbers continued moving in the wrong direction.

He started searching for an alternative approach.

When David found Mastering Diabetes, the concept made sense to him. He was drawn to the possibility of using a plant-based diet and lifestyle changes to improve his diabetes management and potentially reduce his reliance on medication.

He believed it was possible.

But believing in the approach was only the beginning. David still had to understand what was happening inside his body and consistently apply what he was learning.

David's Before and After Results

As David applied what he was learning, the results became measurable.

Header

Before

After

A1c (%)

7.1

5.9

Weight (lbs)

195

167

Exercise

Regular exerciser

Maintained without losing stamina

Energy

Lower

Significantly improved

Sugar Cravings

Strong sweet and salty cravings

No longer experiencing them

David lowered his A1c by 1.2 percentage points while losing approximately 20 pounds. He also noticed changes that couldn't be captured by an A1c measurement or a scale

His energy increased considerably. He no longer felt tired, his sugar cravings disappeared, and he generally felt better.

For someone who had already been committed to exercise, another important result was what didn't change: His stamina.

Maintaining His Active Lifestyle

David had always exercised, so physical activity wasn't something he needed to discover after joining Mastering Diabetes.

Instead, he wondered whether changing the way he ate might interfere with the exercise routine he had already built.

Would he lose stamina? Would his energy suffer? That didn't happen.

David continued exercising while following the Mastering Diabetes approach and found that he was able to maintain his physical activity without sacrificing endurance. At the same time, his overall energy improved.

That experience helped reinforce his confidence in the lifestyle.

He wasn't simply watching his A1c move in a better direction. He was feeling better while continuing to do the activities that were already important to him.

Understanding the Bigger Picture of Insulin Resistance

One of the most important parts of David's experience was learning more about insulin resistance itself.

Before Mastering Diabetes, he didn't necessarily recognize many of the outward signs commonly associated with metabolic dysfunction. He hadn't experienced some of the visible signs he had learned about, and he believes that may have made it easier to underestimate what was happening internally.

Through the program, David developed a greater appreciation for the long-term importance of improving insulin sensitivity and managing blood sugar.

That education changed the way he thought about diabetes.

Rather than viewing an elevated glucose reading as an isolated number, he began thinking about the underlying metabolic health that influenced those numbers and the potential consequences of allowing diabetes to progress over time.

For David, understanding those consequences created another reason to stay consistent.

Learning That Change Takes Time

David also came away from Mastering Diabetes with a more realistic understanding of how metabolic health changes.

He had lived with type 2 diabetes for approximately 15 years.

He couldn't expect everything that contributed to his condition to disappear overnight.

“I didn't realize at the time that diabetes takes a long time to get, and it takes a long time to fix.”

That realization became an important part of his mindset.

David wasn't looking for a miracle or expecting every measurement to change immediately. Instead, he learned to focus on discipline, consistency, and giving his body time to respond.

His own results reinforced that approach. His A1c moved from 7.1% to 5.9%. His weight fell from 195 to approximately 175 pounds.

His energy increased. His sugar cravings disappeared. And he maintained the stamina he needed to continue exercising.

Those changes gave David tangible evidence that his efforts were moving him in the direction he wanted to go.

What David Wants Others to Know

Looking back, David believes joining Mastering Diabetes was worth the investment. The value wasn't limited to being told which foods to eat.

He learned more about himself. He learned more about diabetes. And he developed a better understanding of insulin resistance and why improving insulin sensitivity matters for long-term metabolic health.

That knowledge gave him a framework he could continue applying instead of simply reacting whenever his numbers moved in the wrong direction.

After approximately 15 years with type 2 diabetes, David had found an approach that made sense to him and produced measurable improvements.

His advice to others reflects the lesson he learned along the way: Keep the discipline. Keep the faith. And give the process time to work.

Ready to See Results Like David?

If you've been living with type 2 diabetes and your numbers continue moving in the wrong direction despite your efforts, learning how to improve insulin sensitivity can give you a different way to approach your metabolic health.

Book a free discovery call with one of our advisors and learn how to begin your own transformation.

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About the author 

Robby Barbaro, MPH

Robby Barbaro, MPH is a New York Times bestselling co-author of Mastering Diabetes: The Revolutionary Method to Reverse Insulin Resistance Permanently in Type 1, Type 1.5, Type 2, Prediabetes, and Gestational Diabetes.

Robby was diagnosed with type 1 diabetes at the age of 12 and has been living this lifestyle since 2006. In that time, while eating pounds of fruit every day, his HbA1c has been stable with a current A1c of 5.3%, TIR of 92%, and average total daily insulin use of 30 units.

Robby graduated from the University of Florida and is the cofounder of Mastering Diabetes and Amla Green. He worked at Forks Over Knives for six years before turning his attention in 2016 to coaching people with diabetes full time.

He is the co-host of the annual Mastering Diabetes Online Summit, a featured speaker at VegFest LA, and has been featured on The Doctors, Forks Over Knives, Vice, Thrive Magazine, Diet Fiction, and the wildly popular podcasts the Rich Roll Podcast, Plant Proof, MindBodyGreen, and Nutrition Rounds.

Robby enjoys exercising every day, spending time with friends, and sharing his lifestyle on Facebook, Twitter and Instagram.